Shizuko, Caller of Autumn 144 (Betrayers of Kamigawa)

At the beginning of each player's upkeep, that player adds {G}{G}{G}. Until end of turn, they don't lose this mana as steps and phases end.

NM - $7.60
LP - $6.10
MP - $4.60
HP - $3.10
DMG - $1.60